JPS6230623Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a back-up spring used in sealing means for hydraulic equipment to prevent damage to packing and the like.

Relative movement in the axial or circumferential direction of two members that fit together, such as a piston and a cylinder, a piston rod and a cylinder cover, a rod and a housing in a power steering device, or a pivot shaft and a pivot base, while being loaded by hydraulic pressure. In hydraulic equipment, a gasket or the like made of a rubber-like elastic material is placed in an annular groove cut into one of the two members that move relative to each other in order to seal the gap between the two members. Normally, the gap between the two members is closed by inserting a In order to protect the back of the gasket from getting stuck in the gap and being damaged, a back-up spring made of a synthetic resin material or the like that has greater strength than the material of the gasket is used on the back of the gasket.

1 and 2 show an example of a sealing means using the above-mentioned back-up spring. In the example shown in FIG. In the annular groove 3,
A packing 6 made of a rubber-like elastic material is inserted so as to make elastic contact with the circumferential surface of the other member 2, and both members 1, 2 are attached.
The back part 7 on the side opposite to the pressure-receiving side of the packing 6 is cut out to have an approximately pentagonal cross-section, and this cut-out part is made of a material with greater strength than the material of the packing 6. A back-up spring 10 made of the same material is inserted into the gap 4 of the packing 6.
Protects from being dug inward.

In the other example shown in FIG. 2, a sliding ring 11 made of a highly wear-resistant material such as a fluorine-based synthetic resin is placed in an annular groove 3 of one member 1, and a sliding ring 11 is placed in the annular groove 3 of one member 1 of the other member 2. It is inserted so as to make elastic contact with the circumferential surface and close the gap 4 between the two members 1 and 2, and a rubber-like elastic material is used between the sliding ring 11 and the bottom circumferential surface of the annular groove 3. The manufactured back ring 12 is inserted to urge the sliding ring 11 toward the circumferential surface of the other member 2, and furthermore, the sliding ring 11 and the back ring 12 have a substantially square cross section at both ends in the axial direction. An annular cavity is formed, and a back-up spring 10 made of a high-strength synthetic resin material is inserted into this annular cavity to apply hydraulic pressure that acts alternately on both the upper and lower sides as shown in the figure. This protects the received sliding ring 11 from being wedged into the gap 4 and damaged.

In the above-described sealing means, in order to ensure a protective function for the packing 6 or the sliding ring 11, the back-up spring 10 and the other member 2 are
Although the gap between the back-up spring and the circumferential surface of the back-up spring is set to a minimum, this small gap causes difficulty in fitting the other member 2, and furthermore, the back-up spring is hard. Since this makes insertion into the annular groove 3 difficult, a configuration in which the back-up spring 10 is cut at one point on the circumference so that the annular body can be deformed is widely used. (Refer to Japanese Utility Model Application Publication No. 56-10544) Since the cut of the above-mentioned back-up spring is usually formed in a plane, it causes trouble when the other rod-shaped member is inserted, as shown in Fig. 3. There is a risk. That is, as shown by the solid line in the figure, the back-up spring 10 should be kept in a perfect ring shape when the other member 2 is inserted. One of the two end portions 23 may be displaced radially inward with respect to the other end 24, and if the other member 2 is inserted with such displacement, the back-up spring 10 may be damaged. This is unavoidable, and furthermore, there is a great risk of causing damage to the packing 6 and the like.

In view of the above-mentioned problems with the conventional back-up spring, the present invention aims at cutting a back-up spring formed on an annular body by adding a cutting surface at one point on the circumference to a straight line parallel to the radius of the annular body. and a first cutting plane that is inclined at an acute angle with respect to the end surface of the annular body;
a second cutting plane that is inclined with respect to the cutting plane and whose intersection line with the first cutting plane is included in a plane that is substantially parallel to the central axis of the annular body; One of the resulting end portions is formed into a convex surface, and the other end portion is formed into a concave surface.

Embodiments of the backup spring according to the present invention will be described below based on the drawings. In the embodiment shown in FIGS. 4 to 7, the cut plane includes a straight line parallel to the radius 15 of the annular body and is inclined at an acute angle θ with respect to the end surface 16 of the annular body. 1 cutting plane 20 and a second cutting plane that is inclined with respect to the first cutting plane 20 and whose intersection line 22 with the first cutting plane 20 is included in a plane that is substantially parallel to the central axis 17 of the annular body. 21, one end portion 23 forms a convex surface, and the other end portion 2
4 forms a concave surface.

The cutting surface in the above-mentioned embodiment is formed by applying a cutting tool whose cutting tip is curved into a substantially L-shape to the part of the annular body to be cut, so that the corner of the cutting tip is parallel to the central axis of the annular body. This is done by making the cut so as to pass through the plane of the annular body and maintain an acute inclination angle θ to the end face 16 of the annular body.

When the above-described embodiment is inserted into packing etc. (see Fig. 3), if the other end portion 24 attempts to move radially inward with respect to one end portion 23, both end portions The first cutting planes 20 and 20 of 23 and 24 are in pressure contact with each other, the other end portion 24 is supported by one end portion 23 and prevented from sliding inward in the radial direction, and one end portion 23 is supported by the other end portion 23. When the second cutting planes 21, 21 of both ends 23, 24 are in pressure contact with each other, one end part 23
is supported by the other end portion 24 and prevented from shifting in the radial direction.

As described above, the back-up spring of the present invention has a cutting surface at one cut point on the circumference of the annular body, which includes a straight line parallel to the radius of the annular body and has an acute angle with respect to the end face of the annular body. A first cutting plane that is inclined while maintaining an inclination angle, and a line of intersection with the first cutting plane that is inclined with respect to the first cutting plane is in a plane that is substantially parallel to the central axis of the annular body. One end formed by the cutting is formed into a convex surface, and the other end is formed into a concave surface. Since it is possible to reduce the diameter of the annular body by slightly displacing it in the axial direction with respect to the other end, assembly work can be easily carried out, and the relative radial direction of both ends can be reduced during transportation, handling, assembly, etc. Since the misalignment of the back-up springs is suppressed by the uneven engagement of both end portions, the risk of damage to the back-up springs during assembly work, which was seen in back-up springs using conventional technology, is completely eliminated. Because the end section uses fluid pressure applied laterally to bring the first and second cutting planes into close contact with each other so that no gaps are formed, both packings or back rings made of rubber-like elastic material can be used. Damage caused by digging into the gap between the terminal parts is prevented.

[Brief explanation of drawings]

1 and 2 are cross-sectional views showing the structure of a sealing means using a back-up spring, which is the subject of the present invention, and FIG. 3 is a plan view showing the situation in which trouble occurs in a back-up spring according to the prior art. 4 to 7 show an embodiment of the present invention, FIG. 4 is a sectional view, FIG. 5 is a plan view,
FIG. 6 is a cross-sectional view of the cut plane indicated by the arrow - on FIG. 4, and FIG. 7 is a perspective view showing the shape of the cut portion. 1...One member, 2...The other member, 3...
Annular groove, 4... Gap, 6... Packing, 7... Back, 10... Back spring, 11... Sliding ring, 12... Back ring, 14... Radius,
16... End face, 17... Central axis line, 20... First
cutting plane, 21... second cutting plane, 22...
Intersection line, 23...one terminal portion, 24...other terminal portion.

Claims (1)

[Scope of utility model registration request] The annular body is cut at one point on the circumference, and the cut surface includes a straight line parallel to the radius 15 of the annular body and is inclined at an acute inclination angle θ with respect to the end surface 16 of the annular body. The intersection line 22 between the cutting plane 20 of the annular body and the first cutting plane 20 that is inclined with respect to the first cutting plane 20 is the central axis 1 of the annular body.
7 and a second cutting plane 21 included in a plane substantially parallel to 7, one end portion 23 produced by cutting is formed into a convex surface, and the other end portion 24 is formed into a concave surface. A back spring is being formed.